Health Law's Uneasy Launch

Affordable Care Act Faces Next Hurdles

Nearly four years after President Barack Obama signed his health initiative into law, the Affordable Care Act is officially reshaping America's $2.75 trillion health-care system.

A survivor of bare-knuckle political fights, a U.S. Supreme Court challenge and a technologically disastrous rollout, the law now faces a fundamental test: Can its mix of government subsidies and market-based competition extend health insurance to millions of...